This paper proposed a boiling water batch extraction–ICP-OES method for determining soil available boron (SAB), and compared its determination results with three other methods, i.e., boiling water extraction–curcumin colorimetric method, boiling water extraction–ICP-OES method, boiling water bath extraction–curcumin colorimetric method. By discussing the detection limits, method detection limits, and determination precision and accuracy of the four above methods, and comparing and analyzing six standard reference materials of high, medium, and low available boron contents from different regions and four actual soil samples, the key factors and method correlations of the four methods were explored. The results showed that the proposed method was simpler and more convenient to operate, with lower detection limits, fewer interference factors, and better repeatability, thus it is suitable for batch sample analysis and determination of various sample types. This comparative study can provide reference for laboratories to carry out research on SAB determination methods, and also can provide technical supports in method selection, efficiency improvement and quality assurance for the testing laboratories which conduct soil sample determination of “The Third National Soil Survey”.